Question
Distinguish clearly between the three modes of heat transmission.
✓
Answer
Three modes of heat transmission are conduction, convection and radiation. Their main points of distinction are as follows:
| S. No | Conduction | Convection | Radiation |
| 1. | There is no bodily motion of medium particles. Medium particles vibrate to and fro about their mean positions and pass on thermal energy to the neighbouring particles. | Heat is transferred from one part of system to another by the actual motion of the particles of the system. | Medium has no role as thermal radiation are transmitted without any material medium. |
| 2. | No convection currents are formed. | Convection currents are formed. | Question of formation of convection currents does not arise. |
| 3. | Conduction of heat takes place in solids and few liquids like mercury and molten metals. | Convection of heat takes place in fluids i.e., liquids as well as gases. | Radiant energy directly flows from heat source to the given body at a speed of 3 × 10m8/ s as electromagnetic waves. |
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